\begin{figure}[htb]
	\centering
	
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\rput(7.747647,3.565006){1. Vertex $\mapsto$ one outgoing half-edge}
\usefont{T1}{ptm}{m}{n}
\rput(6.9248734,3.065006){2. Face $\mapsto$ one half-edge}
\usefont{T1}{ptm}{m}{n}
\rput(7.2244534,2.565006){3. Half-edge $\mapsto$ target vertex}
\usefont{T1}{ptm}{m}{n}
\rput(6.835928,2.065006){4. Half-edge $\mapsto$ its face}
\usefont{T1}{ptm}{m}{n}
\rput(7.370127,1.5650061){5. Half-edge $\mapsto$ next half-edge}
\usefont{T1}{ptm}{m}{n}
\rput(8.40877,1.0650061){6. Half-edge $\mapsto$ opposite half-edge (optional)}
\usefont{T1}{ptm}{m}{n}
\rput(7.662061,0.56500614){7. Half-edge $\mapsto$ previous half-edge}
	\end{pdfpic} 
	\caption{Illustration of Half-edge structure}
	\label{fig:halfedge}

\end{figure}